Tag Archives: baryon

A Word on Quarks…

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I have talked extensively about atoms and the bits which hold them together but, perhaps I have left out key details about the forces which bind them and keep them happy.


Each particle of an atom carries an electrical charge as well as a “color charge” (see below). Most people know what an electrical charge is from grade school. Remember that two magnets repel if their + or – (sometimes North and South, respectively) sides are pointed together and attract if they are mixed, e.g. + and – or – and +. Taking a more scientific look at it, a + is equivalent to a charge of 1 and a – is equivalent to a charge of (-1). Having a neutral charge means zero charge.

If a proton, having a charge of 1, and an electron, having a charge of (-1) are bound together, they are said to be in equilibrium. In this state 1+(-1)=0. This atom would have a total, net, charge of 0 and be somewhat stable. Likewise, an atom with two electrons and one proton would have a net charge of: 1+(-1)+(-1) = -1. This atom would be more negative and may even give up an electron to another atom if need be (called a valance electron).

So.. you understand electrical charges, right? Electrons have a -1 and protons have a +1… neutrons are in the middle with zero… Simple enough.

Color Charges

Now for Color Charges! Color has a charge? Not really. When talking about subatomic particles, the “color” is really a property which has be labeled “color”. It is just a arbitrary name. There are three “colors” and three corresponding “anti-colors”. If you combine an electrical charge of -1 and +1, you get 0, right? Well, if you combine Blue and Anti-Blue (yellow, the opposite of blue), you get white. White is effectively zero. Creepy stuff which probably exceeds the scope of a simple tid-bit of info.


As much fun as these electrons and colors are, this is about Quarks, so lets get on topic. A quark is a “point particle” and has a very tiny size. Quarks always form in groups of either three or two (theoretically more).

Anything made of Quarks is called a Hadron. Hadrons made of two Quarks, typically a quark and an anti-quark, are called Mesons, while Hadrons made of three Quarks are called Baryons. A proton and a neutron are both baryons.

WOW! You mean that just as an atom is actually a system of little particles, a proton and neutron are also actually tiny systems of particles??? YES!


= electon, neutron, Proton

= electron+{(up-quark)(down-quark)(down-quark)}+{(up-quark)(up-quark)(down-quark)}

WOW! So a single atom could be made of so many particles?! YES!

Quarks come in six types and six corresponding anti-types. They have arbatrary names which are NOT indicative of any qualities. For example, the “Top” quark is not actually on top of anything. It’s just a name. They could have called it the “steve” or “bob” quark. Lol

The Quarks:

Top Charmed Up

Bottom Strange Down

each has an anti-quark: anti-up, anti-down, etc.

Top and Bottom are third generation, the biggest.

Charged and Strange are second generation, the middle.

Up and Down are first generation, the smallest.

Interestingly, generations 3 and 2 tend to decay, rapidly, into generation 1. All “stable” matter in the universe is made of generation 1 particles. The electron and it’s family, the leptons, have a similar system going on in which the electron is of generation 1.

See http://en.wikipedia.org/wiki/File:Standard_Model_of_Elementary_Particles.svg

A great chart!